Design and testing of a hybrid electromagnetic damping device for automotive applications

Abstract

This study proposes a new design concept for combining a viscous fluid damper (VFD) with an eddy current damper (ECD). Three main concepts were thoroughly discussed: the magnetic system, the conductive material, and the housing. In particular, the excitation circuit and magnetic field were applied from the exterior of the main chamber of the VFD to minimize the intrusive risks introduced into the damper when trying to connect an internal magnetic system to an external power source. Experimental investigations on a test rig developed for this purpose were carried out in this work. The design aimed to generate eddy currents in an oscillating cylinder made of copper placed around an existing real-world car damper and secured to its moving rod. When exposed to an electromagnetic field, the newly designed system rapidly generated an extra level of damping in addition to the initial damping effect provided by the viscous mechanism. The obtained results showed that applying an electric current of only 1A increased the amplitude of the drag force by 12 % for an electrode with a thickness of 1.5 mm. A magnetic saturation phenomenon resisted any extra increase in the current. Making the metal conductor thicker is expected to increase the volume of the conductor in which the currents are flowing and, consequently, increase the damping effect.